1. Field of the Invention
The present invention provides a rotary encoder and an optical wheel for a rotary encoder. In particular, the present invention provides a rotary encoder and an optical wheel capable of effectively preventing the influence of dust or particles on the functions thereof. The present invention further provides a linear encoder, and more particularly, to a linear encoder capable of effectively preventing the influence of dusts or particles on the functions thereof.
2. Descriptions of the Related Art
Generally, a rotary encoder comprises a light source, an optical sensor and a code disk. The code disk is disposed between the light source and the optical sensor and can rotate relative to the light source and the optical sensor.
The code disk comprises a plurality of light transmitting regions alternating with a plurality of light non-transmitting regions. The light transmitting regions allow light emitted by the light source to pass therethrough and be sensed by the optical sensor. The non-transmitting regions block the light emitted by the light source from passing therethrough and, thus, prevent the light from being sensed by the optical sensor.
The number of the light transmitting regions and the light non-transmitting regions of the code disk has an influence on the resolution of the rotary encoder. Specifically, the larger the number of the light transmitting regions and the light non-transmitting regions there are, the higher the resolution of the rotary encoder will be. However, an increased number of the light transmitting regions and the light non-transmitting regions lead to smaller sizes of the light transmitting regions and the light non-transmitting regions, which makes the production of the code disk more difficult and adds to the production cost.
Furthermore, as the light transmitting regions become smaller in size, they become more susceptible to dust or particles. In detail, if the dust particles fall on a light transmitting region with a small size, the light transmitting region might be sheltered to prevent light from passing therethrough, thus degrading the accuracy or reliability of the rotary encoder. To overcome the aforesaid shortcoming, the rotary encoder must be preferably sealed during assembled to block entry of dusts or particles from the environment into the rotary encoder. However, this undesirably leads to an increase in the assembly cost of the rotary encoder.
In addition to the rotary encoder, linear encoders also have the same shortcomings.
In view of this, an urgent need exists in the art to provide a rotary encoder and a liner encoder capable of overcoming the aforesaid shortcomings.